1. Field of the Invention
The present invention relates to a parking brake operating apparatus, and more particular it relates to a technique for preventing occurrence of an erroneous operation upon spring-up of an operating member resulted from shake of a vehicle body during a rough road running.
2. Discussion of Related Art
A parking brake operating apparatus is operated by a driver to actuate a parking brake of a vehicle, and it includes (a) a supporting member, (b) an operating member, (c) a ratchet, and (d) a pawl has been known. The supporting member is disposed in a vehicle body integrally therewith. The operating member is disposed in the supporting member pivotally rotatable i.e., pivotable about a first axis within a limited angle, and is brake-operated from an initial position thereof to actuate the parking brake. The ratchet has many engaging teeth formed along an arc centering on the first axis, and is disposed in one of the supporting member and the operating member integrally therewith.
The pawl is disposed in other of the supporting member and the operating member, and rides over the ratchet and then engages therewith. In detail, the pawl rides over the many engaging teeth during the braking operation of the operating member, but it engages with many engaging teeth upon the braking operation to prevent returning pivotal movement of the operating member toward the initial position side, to maintain the actuating state of the parking brake.
Patent documents 1 to 3 (Patent document 1: Japanese Patent Application Publication No. 2004-13746; Patent document 2: Japanese Utility Model Application Publication No. S64-39166; Patent document 3: Japanese Patent Application Publication No. 2002-145028) disclose examples of the parking brake operating apparatuses. Among them, the patent documents 1 and 2 disclose one type in which an operating lever as the operating member is disposed at side of a driver's seat, and it is held in a substantially horizontal posture with a grip portion extending forward in the vehicle in the initial position. The patent document 3 discloses other type in which an operating lever is disposed at a console box portion in front of the driver's seat, and it is held in a substantially vertical posture with a grip portion extending upward in the vehicle in the initial position.
However, the parking brake operating apparatuses disclosed in the patent documents 1 and 2 suffer from following drawback. The operating lever may spring up due to large shake of the vehicle body running on the rough road, which allows the pawl to ride over the first engaging tooth for pivoting of the operating lever. As a result, a parking lamp may be erroneously lightened. Especially, in recent years, a demand as an interior equipment is increasingly required for the operating lever. Specifically, in view of balance with a side edge shape and an inclined angle of adjacent interior equipment, the operating lever, in the initial position thereof, is not held in the horizontal posture but is held in an inclined posture inclined by a predetermined angle. In such case, the operating lever may spring up from the initial position more easily.
For preventing such spring-up of the operating lever, following manners are considered. One manner is to increase a bias force of a bias means for biasing the pawl, so that load of the pawl required to ride over the first engaging tooth increases. Other manner is to bias the operating lever toward the initial position by a plate spring and the like. However, in the former case, the increase of bias force for the pawl leads to an increase of operating force of a release knob which is pushed upon releasing of the parking brake, thus worsening an operability. In the latter case, the additional member required for biasing the operating lever toward the initial position increases the cost.
Incidentally, in the apparatus disclosed in the patent document 2, in the state with the operating lever being held in the initial position, the pawl rides on a protruded portion protruded larger than the engaging teeth. As a result, there is fear that the operating lever pivoting from the initial position tends to ride over the engaging teeth more easily. Also feared is that, upon returning pivotal movement of the operating lever for the brake releasing, the pawl abuts onto the protruded portion, which requires strong a push-in of the release knob, thus worsening the operability of the operating member.
In the parking brake operating apparatus disclosed in the patent document 3, the operating lever disposed in the substantially vertical posture may easily fall down by a small shake to be pivoted from the initial position. To avoid this, a positioning means is provided for engaging a grip portion at a top of the operating lever with the console box for the positioning. However, such positioning means using the engagement between the operating lever and the console box suffers from following drawbacks. Firstly, both the operating lever and the console box become complicated in the shape thereof which leads to increase of the cost. Secondary, a loose positioning resulted from a slight dimensional error or an assembling error may shake the operating lever or disengage the positioning means, which causes a fall-down of the operating lever from the initial position.
To the contrary, a tight positioning by the positioning means requires the larger actuating force of the operating lever, thereby worsening the operability. Alternatively, it establishes a half or semi engaged state thereof, resulting in the fall-down of the operating lever during the vehicle running, upon returning pivotal movement of the operating lever toward the initial vertical position.
The present invention is made in view of the above mentioned circumstance and therefore has an object to prevent erroneous operation such as lightening of a brake lamp from occurring resulting from a spring-up of the operating member upon shaking of the vehicle body during the vehicle running on the rough road easily and cheaply, without worsening the operability or increasing the number of members.